Download IR 29 Reference Manual

General description
A fixed gas warning system consists of a transmitter and a controller unit (GMA, not included). The
transmitter and the controller are interconnected by a shielded remote measurement cable. The
transmitter converts the gas concentration into an electrical measuring signal. The evaluation of the
measuring signal proportional to the existing gas concentration takes place at the controller (GMA).
The extensive electronics assumes various tasks which, on the one hand, facilitates operation and
maintenance and, on the other hand, significantly enhances operational safety and measuring
accuracy. The transmitter features the following:
• Concentration display on the display or remote control
• Settings without opening the housing with the RC 2 or RC 3 remote control
• Compensation of temperature influences
• Ex-protection in the temperature range -20 to +55 °C
• Functional test in the temperature range (see sensor specification)
• Permanent status display (operation / fault) at the transmitter
Measuring methods
The sensors installed in the IR 29 transmitter work according to the IR absorption principle.
Alignment to the gas type being monitored takes place using specific optical filters combined with
suitable characteristics. The reduced IR radiation at the detector is converted into an electrical
signal. This signal is amplified in the IR 29, filtered and used for the display or measured value
transfer. Due to its design with two radiation sources, the measurement assembly offers a powerful
signaling function and is less sensitive to interfering influences, such as deterioration of the
radiators or temperature deviations. Soiling of the optics can also be compensated up to a certain
degree. Due to the design and additionally available temperature and pressure compensation,
influence caused by ambient conditions is almost entirely eliminated.
The electronics of the IR 29 transmitter converts the measuring signal into a linear measured value
output 4...20 mA.
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